From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 70EE5C7618B for ; Tue, 23 Jul 2019 15:19:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5048B223A0 for ; Tue, 23 Jul 2019 15:19:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729772AbfGWPTu (ORCPT ); Tue, 23 Jul 2019 11:19:50 -0400 Received: from asavdk3.altibox.net ([109.247.116.14]:51539 "EHLO asavdk3.altibox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728591AbfGWPTu (ORCPT ); Tue, 23 Jul 2019 11:19:50 -0400 Received: from ravnborg.org (unknown [158.248.194.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by asavdk3.altibox.net (Postfix) with ESMTPS id 54655200D5; Tue, 23 Jul 2019 17:19:41 +0200 (CEST) Date: Tue, 23 Jul 2019 17:19:39 +0200 From: Sam Ravnborg To: Andrzej Pietrasiewicz Cc: Neil Armstrong , Maxime Ripard , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Matthias Brugger , Thierry Reding , Laurent Pinchart , Shawn Guo , kernel@collabora.com, linux-samsung-soc@vger.kernel.org, linux-rockchip@lists.infradead.org, Sean Paul , Krzysztof Kozlowski , Jonathan Hunter , David Airlie , Chen-Yu Tsai , Kukjin Kim , NXP Linux Team , Dave Airlie , Thomas Zimmermann , Jonas Karlman , linux-arm-msm@vger.kernel.org, intel-gfx@lists.freedesktop.org, Jyri Sarha , Alexios Zavras , Mamta Shukla , linux-mediatek@lists.infradead.org, Rodrigo Vivi , linux-tegra@vger.kernel.org, Thomas Gleixner , Vincent Abriou , linux-arm-kernel@lists.infradead.org, Jernej Skrabec , amd-gfx@lists.freedesktop.org, Tomi Valkeinen , Greg Kroah-Hartman , Seung-Woo Kim , Douglas Anderson , Todor Tomov , Kyungmin Park , Huang Rui , Pengutronix Kernel Team , Alex Deucher , freedreno@lists.freedesktop.org, Christian =?iso-8859-1?Q?K=F6nig?= , Gerd Hoffmann Subject: Re: [PATCH v4 14/23] drm/tilcdc: Provide ddc symlink in connector sysfs directory Message-ID: <20190723151939.GA13718@ravnborg.org> References: <20190723090532.GA787@ravnborg.org> <3ad60be5-49cf-4017-4b74-53a2d6272deb@collabora.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <3ad60be5-49cf-4017-4b74-53a2d6272deb@collabora.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-CMAE-Score: 0 X-CMAE-Analysis: v=2.3 cv=dqr19Wo4 c=1 sm=1 tr=0 a=UWs3HLbX/2nnQ3s7vZ42gw==:117 a=UWs3HLbX/2nnQ3s7vZ42gw==:17 a=jpOVt7BSZ2e4Z31A5e1TngXxSK0=:19 a=8nJEP1OIZ-IA:10 a=QX4gbG5DAAAA:8 a=6mu-9OIm9KcVJ4iDVDwA:9 a=wPNLvfGTeEIA:10 a=AbAUZ8qAyYyZVLSsDulk:22 Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org Hi Andrej. On Tue, Jul 23, 2019 at 02:44:50PM +0200, Andrzej Pietrasiewicz wrote: > Hi Sam, > > W dniu 23.07.2019 o 11:05, Sam Ravnborg pisze: > > Hi Andrzej > > > > On Thu, Jul 11, 2019 at 01:26:41PM +0200, Andrzej Pietrasiewicz wrote: > > > Use the ddc pointer provided by the generic connector. > > > > > > Signed-off-by: Andrzej Pietrasiewicz > > > --- > > > drivers/gpu/drm/tilcdc/tilcdc_tfp410.c | 1 + > > > 1 file changed, 1 insertion(+) > > > > > > diff --git a/drivers/gpu/drm/tilcdc/tilcdc_tfp410.c b/drivers/gpu/drm/tilcdc/tilcdc_tfp410.c > > > index 62d014c20988..c373edb95666 100644 > > > --- a/drivers/gpu/drm/tilcdc/tilcdc_tfp410.c > > > +++ b/drivers/gpu/drm/tilcdc/tilcdc_tfp410.c > > > @@ -219,6 +219,7 @@ static struct drm_connector *tfp410_connector_create(struct drm_device *dev, > > > tfp410_connector->mod = mod; > > > connector = &tfp410_connector->base; > > > + connector->ddc = mod->i2c; > > > drm_connector_init(dev, connector, &tfp410_connector_funcs, > > > DRM_MODE_CONNECTOR_DVID); > > > > When reading this code, it looks strange that we set connector->ddc > > *before* the call to init the connector. > > One could risk that drm_connector_init() used memset(..) to clear all > > fields or so, and it would break this order. > > I verified the code of drm_connector_init() and cannot find any memset() > invocations there. What is your actual concern? My concern is that drm_connector_init() maybe sometime in the future will init all fileds in drm_connector, so we loose any assingments done to drm_connector from *before* we called the init function. Moving the assignment to after drm_connector_init() would not let us depend on the actual implmentation of drm_connector_init(). Sam